diff --git a/include/openmc/nuclide.h b/include/openmc/nuclide.h
index a936ac0102..a1571ea58e 100644
--- a/include/openmc/nuclide.h
+++ b/include/openmc/nuclide.h
@@ -93,7 +93,7 @@ public:
   std::vector<UrrData> urr_data_;
 
   std::vector<std::unique_ptr<Reaction>> reactions_; //!< Reactions
-  std::array<size_t, 892> reaction_index_; //!< Index of each reaction
+  std::array<size_t, 902> reaction_index_; //!< Index of each reaction
   std::vector<int> index_inelastic_scatter_;
 
 private: